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Iron-catalyzed urea synthesis: dehydrogenative coupling of methanol and amines†
Chemical Science ( IF 7.6 ) Pub Date : 2018-04-09 00:00:00 , DOI: 10.1039/c8sc00775f
Elizabeth M Lane 1 , Nilay Hazari 2 , Wesley H Bernskoetter 3
Affiliation  

Substituted ureas have numerous applications but their synthesis typically requires the use of highly toxic starting materials. Herein we describe the first base-metal catalyst for the selective synthesis of symmetric ureas via the dehydrogenative coupling of methanol with primary amines. Using a pincer supported iron catalyst, a range of ureas was generated with isolated yields of up to 80% (corresponding to a catalytic turnover of up to 160) and with H2 as the sole byproduct. Mechanistic studies indicate a stepwise pathway beginning with methanol dehydrogenation to give formaldehyde, which is trapped by amine to afford a formamide. The formamide is then dehydrogenated to produce a transient isocyanate, which reacts with another equivalent of amine to form a urea. These mechanistic insights enabled the development of an iron-catalyzed method for the synthesis of unsymmetric ureas from amides and amines.

中文翻译:

铁催化尿素合成:甲醇和胺的脱氢偶联†

取代脲有许多应用,但它们的合成通常需要使用剧毒的起始材料。在此,我们描述了第一种通过甲醇与伯胺脱氢偶联选择性合成对称脲的贱金属催化剂。使用钳形负载铁催化剂,生成了一系列尿素,分离产率高达 80%(相当于催化转化率高达 160),且 H 2为唯一副产物。机理研究表明,从甲醇脱氢开始逐步生成甲醛,甲醛被胺捕获,生成甲酰胺。然后甲酰胺脱氢产生暂时的异氰酸酯,其与另一当量的胺反应形成脲。这些机理见解使得铁催化方法得以开发,用于从酰胺和胺合成不对称脲。
更新日期:2018-04-09
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